a. Field of the Invention
The present invention relates to electrometallurgy, and, in particular, to ingot electroslag remelting apparatus.
B. Description of the Prior Art
The present invention may find a most effective application in the manufacture of relatively large ingots requiring the remelting of several consumable electrodes fed successively into the melting space.
In electroslag remelting of such ingots a critical problem is to replace in the course of remelting a melted consumable electrode by a fresh one in a manner to prevent the liquid metal inside the mould from solidifying during the time the consumable electrode is out of the melting space.
In apparatus for electroslag remelting of ingots of relatively large diameters, the continuity of melting is ensured by auxiliary electrodes located alongside the main one over the surface of the slag bath in the mould. When the melted main electrode is being removed, current is supplied through the auxiliary electrodes thereby maintaining required thermal conditions during the replacement of the main electrode.
In apparatus for manufacturing ingots whose diameters make it impossible to place more than one electrode over the mould, use is made of at least two mobile electrode holders to prepare in advance a fresh electrode and to effect the replacement as quickly as possible.
There is known in the art an apparatus for electroslag remelting of ingots with alternate feeding of consumable electrodes into the melting space, vertical guides in the form of columns provided on both sides of the mould for the travel on each of them of a carriage with an electrode holder electrically connected to a power source (cf. Austrian Pat. No. 286514, Cl.31b 2/03, 1973). Each carriage is mounted on a corresponding column and rotatable about the column axis thereby ensuring the motion of the electrode holder along a circular arc in a horizontal plane.
Each carriage is geared to two independent drive means: a vertical travel drive means and a rotation drive means.
To replace a melted consumable electrode by a fresh one, the vertical travel drive means is actuated to lift the carriage with the electrode holder and the melted consumable electrode above the top edge of mould walls, then the rotation drive means is actuated to move the electrode holder out of the mould zone. Another carriage with the electrode holder carrying a fresh consumable electrode is first rotated horizontally with the aid of a drive means at a height allowing the consumable electrode to clear the top edge of the mould walls, then lowered to a required level by energizing the vertical travel drive means.
Thus, the displacement of each electrode holder, when replacing a melted consumable electrode by a fresh one, involves two kinds of motion, thereby requiring a sequential operation of the corresponding drive means and relatively much time. Moreover, it is impossible to move the replacing consumable electrode into the mould zone until the consumable electrode being replaced is lifted above the top edge of the mould walls and rotated partially in a horizontal plane. As the consumable electrode is out of the melting space for a prolonged time, this giving rise to such defects as peeling, surface corrugations and the like.